
\documentclass[times,10pt,twocolumn]{article} 
\usepackage[english]{babel}
\usepackage{enumerate}
\usepackage{graphicx}
\usepackage{amsmath,amssymb,amstext,amsthm}
\usepackage{comment}
\usepackage{color}
\usepackage{wrapfig}

\usepackage{tikz}
\usetikzlibrary{arrows,automata,backgrounds,calc,chains,fadings,folding,decorations.fractals,decorations.pathreplacing,fit,patterns,positioning,mindmap,shadows,shapes.geometric,shapes.symbols,through,trees,plotmarks}

\colorlet{mgray}{black!60}

\begin{document}
\pagestyle{empty}
\scalebox{5}{
  \begin{tikzpicture}[very thick,mgray]
    \coordinate (center) at (0,0);
    \coordinate (ul) at (-1mm,1mm);
    \coordinate (ur) at (1mm,1mm);
    \coordinate (ll) at (-1mm,-1mm);
    \coordinate (lr) at (1mm,-1mm);
    \shadedraw [draw=none,top color=mgray!25,bottom color=mgray,shading=axis,shading angle=45] (center) circle (2mm);
    \draw [white] (ul) -- (lr);
    \draw [white] (ur) -- (ll);
  \end{tikzpicture}
}
\end{document}


